Questions and Answers
1. What types of medical products contain phthalate
plasticisers ?
There are three main types of medical products containing
phthalates:
Containers: including flexible bags for intravenous or
nutritional fluids, solutions, drug and anticoagulants. They are also used to
collect and store blood and plasma (IV blood bags) and to collect urine.
Flexible tubing: including blood circuit tubes, infusers,
catheters and endotracheal tubes.
Protective devices: including gloves and oxygen tents.
2. What phthalates are used in the manufacture of medical
devices ?
By far the most widely used is DEHP (di-2-ethylhexyl
phthalate), sometimes also known as DOP (di-octyl phthalate).
3. Why is DEHP preferred to other phthalates?
Every phthalate offers slightly different properties. DEHP is
the preferred phthalate for medical devices because of its properties which
include maintaining flexibility at low temperatures combined with a resistance
to high temperature sterilisation.
4. Is it true that patients are being put at risk as a
result of exposure to DEHP from PVC medical devices?
No. There is no evidence to suggest that patients are at being put at risk.
To the contrary, PVC medical products have been used for more than 40 years in
healthcare establishments around the world and there is not one known case of a
patient having suffered as a result. There are millions of healthy people today
who have benefited from having been treated with life-saving PVC medical
products.
One of the world’s leading manufacturers of medical
devices, Baxter, says that it believes that have been between five and seven
billion patient days of acute exposure and between one and two billion patient
days of chronic exposure to DEHP-plasticised medical products.
5. So, are they safe to use?
Used properly and in the way that they are, we believe – as
do the medical authorities – that they are safe to use. In fact, in Europe,
PVC containers for blood, blood components and for aqueous solutions for
intravenous infusion are the only type listed for use in the European
Pharmacopoeia. Other materials can only be used subject to approval in each case
by the national authority responsible for licensing them.
Medical devices in Europe are strictly regulated by the
EU’s Medical Device Directive (93/42/EEC). In the USA they are similarly
regulated by the Federal Drug Administration, FDA.
6. But is it true that phthalates migrate from these
products and are being absorbed by patients ?
Like many components of both man-made and natural products,
phthalate plasticisers may be absorbed in small quantities by the fluids they
come into contact with. This is a known occurrence and therefore the safety of
such products is regularly reviewed and stringently monitored by both industry
and regulatory authorities.
7. How are patients being exposed and by how much ?
The potential exposure route to a plasticiser occurs when a patient receives
fluids intravenously. How much plasticiser is released depends on the fluid
properties, storage time, temperature and the type of plasticiser used. However,
the amount that might migrate is very small and phthalates are quickly
metabolised and eliminated from the human body.
8. What about the risk to dialysis patients or those in
critical care units who receive prolonged treatment using PVC products ?
There is no evidence to suggest that they are at risk. Even
the amounts that such patients would be subjected to are too low to cause
concern. An independent review that examined the health risk to humans of
exposure to DEHP, particularly via medical devices, concluded that an increased
cancer risk due to DEHP is unlikely even among maximally exposed haemedialysis
patients.
9. It is being said that there is a cancer risk from DEHP.
Is this true ?
Claims by environmental and healthcare groups that medical
patients may be exposed to a cancer risk as a result of being treated using
medical products containing the plasticiser are unfounded. The World Health
Organisation and the European Commission have both conducted extensive reviews
of DEHP but neither has classified the phthalate as a human carcinogen. Health
Canada classifies it as ‘unlikely to be carcinogenic to humans’.
In the United States, DEHP is listed as a probable human
carcinogen by the Environmental Protection Agency (EPA) but this is based on
rodent studies and there is disagreement even within the EPA as to whether the
classification is correct.
In rodent studies, during which DEHP was administered at very
high doses, there has been evidence of liver cancer. However, the significant
species differences that exist between the ways in which a human liver and a
rodent liver respond to DEHP means that carcinogenicity in humans from DEHP
exposure is extremely unlikely.
10. Is it true that DEHP causes human reproductive problems?
No. There is no evidence that phthalates cause human
reproductive problems. It is true that some phthalates, at high dose levels,
have been shown to cause reproductive effects in rats and mice. However, the
relevance of these findings to humans is limited due to the dose level being far
in excess of human exposure and the fact that primates appear to be resistant to
the reproductive effects seen in rodents.
A number of studies in monkeys, especially a recent one
carried out in Japan, have shown that at extremely high dose levels (500,000
times higher than expected human exposure) DEHP has no effect on testes and
ovaries.
11. But isn’t DEHP labelled as harmful to reproduction?
In line with our policy of product stewardship and based on the rodent data,
ECPI members have self-classified two phthalates as possibly harmful to
reproduction in line with EU classification and labelling legislation. This
legislation requires even high dose data with limited references to human risk
to be used for classification and labelling purposes.
12. Why are some phthalates, including DEHP, classified as
endocrine disrupters ?
We do not believe they are endocrine disrupters based on the
wealth of scientific research that is available. They appear on some lists of
‘possible endocrine disrupters’ due to isolated studies which showed a
possible link to estrogenic activity. However, these studies have now been
superseded by more recent research and it has been proven not to be the case. As
reported in the February 20 1999 issue of the Endocrine/Estrogen Newsletter, the
US Food and Drug Administration (FDA) has conducted both in vitro and in vivo
tests on DEHP and other phthalates and found them not to be oestrogenic.
13. The industry has claimed that the use of DEHP in blood
bags actually helps prolong the life of blood. Is this true ?
Yes. The small amounts of plasticiser that migrates from a blood bag does
help preserve blood. This is another benefit of using plasticised PVC. The
amounts are so small that they do not pose a health risk.
14. Why is Plasticised PVC preferred over other plastics or
materials ?
Sterilisation: Plasticised PVC maintains its high integrity
under extreme hot and cold temperatures
Transparency: Plasticised PVC has exceptionally good clarity
so that the flow of liquids through tubes, for example, can be carefully
monitored.
Flexibility: It is highly resistant to ‘kinking’.
Therefore it reduces the risk of interruption to the flow of fluids in tubes.
Strength and resistance: It has the strength and durability
to resist tears, protecting both doctors and patients at the same time as
preventing the spread of infection and germs.
Cost: Plasticised PVC is inexpensive. It allows hospitals to
use quality disposable items that help reduce infection rates.
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